Incorrect string value: '\xF0\x9F\x8E\xB6\xF0\x9F...' MySQL

I was finally able to figure out the issue. I had to change some settings in mysql configuration my.ini This article helped a lot http://mathiasbynens.be/notes/mysql-utf8mb4#character-sets

First i changed the character set in my.ini to utf8mb4 Next i ran the following commands in mysql client

SET NAMES utf8mb4; 
ALTER DATABASE dreams_twitter CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci;

Use the following command to check that the changes are made

SHOW VARIABLES WHERE Variable_name LIKE 'character\_set\_%' OR Variable_name LIKE 'collation%';

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I had hit the same problem and learnt the following-

Even though database has a default character set of utf-8, it's possible for database columns to have a different character set in MySQL. Modified dB and the problematic column to UTF-8:

mysql> ALTER DATABASE MyDB CHARACTER SET 'utf8' COLLATE 'utf8_unicode_ci'

mysql> ALTER TABLE database.table MODIFY COLUMN column_name VARCHAR(255) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL;

Now creating new tables with:

> CREATE TABLE My_Table_Name (
    twitter_id_str VARCHAR(255) NOT NULL UNIQUE,
    twitter_screen_name VARCHAR(512) CHARACTER SET utf8 COLLATE utf8_unicode_ci,
    .....
  ) CHARACTER SET utf8 COLLATE utf8_unicode_ci;

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It may be obvious, but it still was surprising to me, that SET NAMES utf8 is not compatible with utf8mb4 encoding. So for some apps changing table/column encoding was not enough. I had to change encoding in app configuration.

Redmine (ruby, ROR)

In config/database.yml:

production:
  adapter: mysql2
  database: redmine
  host: localhost
  username: redmine
  password: passowrd
  encoding: utf8mb4

Custom Yii application (PHP)

In config/db.php:

return [
    'class' => yii\db\Connection::class,
    'dsn' => 'mysql:host=localhost;dbname=yii',
    'username' => 'yii',
    'password' => 'password',
    'charset' => 'utf8mb4',
],

If you have utf8mb4 as a column/table encoding and still getting errors like this, make sure that you have configured correct charset for DB connection in your application.

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Change database charset and collation

ALTER DATABASE
    database_name
    CHARACTER SET = utf8mb4
    COLLATE = utf8mb4_unicode_ci;

change specific table's charset and collation

ALTER TABLE
    table_name
    CONVERT TO CHARACTER SET utf8mb4
    COLLATE utf8mb4_unicode_ci;

change connection charset in mysql driver

before

charset=utf8&parseTime=True&loc=Local

after

charset=utf8mb4&collation=utf8mb4_unicode_ci&parseTime=True&loc=Local

From this article https://hackernoon.com/today-i-learned-storing-emoji-to-mysql-with-golang-204a093454b7

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According to the create table statement, the default charset of the table is already utf8mb4. It seems that you have a wrong connection charset.

In Java, set the datasource url like this:

jdbc:mysql://127.0.0.1:3306/testdb?useUnicode=true&characterEncoding=utf-8`.

?useUnicode=true&characterEncoding=utf-8 is necessary for using utf8mb4.

It works for my application.

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I had use an emoji in my string that was the reason for this error.

So make sure you are not using some incorrect string that is not valid to save into the database.

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FOR SQLALCHEMY AND PYTHON

The encoding used for Unicode has traditionally been 'utf8'. However, for MySQL versions 5.5.3 on forward, a new MySQL-specific encoding 'utf8mb4' has been introduced, and as of MySQL 8.0 a warning is emitted by the server if plain utf8 is specified within any server-side directives, replaced with utf8mb3. The rationale for this new encoding is due to the fact that MySQL’s legacy utf-8 encoding only supports codepoints up to three bytes instead of four. Therefore, when communicating with a MySQL database that includes codepoints more than three bytes in size, this new charset is preferred, if supported by both the database as well as the client DBAPI, as in:

e = create_engine(
    "mysql+pymysql://scott:tiger@localhost/test?charset=utf8mb4")
All modern DBAPIs should support the utf8mb4 charset.

enter link description here

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